This invention concerns a novel type of a Solid State Tissue Equivalent Detectors (SSTEDs) that combines semiconductor device construction principles and organic photo-conductor technology. The detector is an improvement on the invention disclosed in U.S. Pat. No. 8,350,225, which is hereby incorporated by reference in its entirety, issued to the same inventor. The invention is a solid state device that has an active region made of organic material; the entire device (with the exception of the electrical contacts) can be composed of organic material; it is small and lightweight; will operate at a relatively low voltage; and, will have a tissue equivalent response based on its constituent organic components.
The device is an improvement on the device presented in U.S. Pat. No. 8,350,225 with a modification introducing new electrodes. The new electrodes effectively make regions of the device, which are connected to the active region, act like Field Effect Transistors (FETs). The new electrodes act like gate regions of a standard FET and create field effect within regions of the device. Field effect refers to the modulation of the electrical conductivity of a material by the application of an external electric field. Thus, when the device is at a resting voltage and the FETs' resistance is very high, the active region is insulated preventing charge within the active region from draining. The new gate electrodes allow charges to be cleared from the active region when positive or negative voltage is applied to the gates thereby reducing the resistance of the FETs.